1. Field of the Invention
The present invention generally relates to a single-reel recording tape cartridge and, more particularly, to the single-reel recording tape cartridge of a kind including a leader member which is, when in use, captured by a catch member, forming a part of an automatic tape threading mechanism built in the tape drive, so that a length of magnetic recording tape can be drawn out of the cartridge.
2. Description of the Prior Art
The tape cartridge of the kind referred to above is well known in the art and is disclosed in, for example, the Japanese Laid-open patent publication No. 11-232826, published Aug. 27, 1999. In general, the single-reel recording tape cartridge includes a generally rectangular cartridge housing having a reel chamber defined therein, and a single reel freely rotatably accommodated within the reel chamber and having a roll of a length of magnetic recording tape mounted thereon. The length of magnetic recording tape has one end anchored to a reel hub and the opposite, free end coupled with a leader piece. When the cartridge is in use, having been loaded into a tape drive for data recording or retrieval, a catch member forming a part of an automatic reeling mechanism built in the tape drive captures the leader piece to draw the magnetic recording tape out of the cartridge housing for data recording or retrieval in cooperation with a magnetic read/write head.
The leader piece disclosed in the publication No. 11-232826 is in the form of a metal pin of a uniform diameter over the length thereof and having its opposite ends formed with an engagement boss of a diameter greater than that of the metal pin. The leader piece disclosed in this publication is, when the cartridge is not in use, retained at a retracted position with its opposite engagement bosses receded within generally U-shaped bearing recesses defined in top and bottom panels of the cartridge. Barrier walls for preventing a spring element from being displaced in position are formed adjacent the associated bearing recesses so as to protrude parallel to the top and bottom panels, respectively. The spring element is in the form of a torsion spring having opposite spring arms, one of which is formed with a generally arcuate portion adapted to engage the corresponding engagement boss when the leader piece is held in the retracted position.
According to this publication, connection between the leader piece, that is, the metal pin and the free end of the magnetic recording tape is achieved by turning the free end of the magnetic recording tape around the metal pin to form a tape loop around the metal pin and mounting an elastic C-clip externally around the tape loop, with the intervention of a cushioning sleeve between the metal pin and the C-clip, to secure the free end of the magnetic recording tape to the metal pin. The metal pin has upper and lower, thin-walled annular flanges formed integrally therewith so as to protrude radially outwardly therefrom and positioned on respective sides of the tape loop, or the C-clip connecting it to the metal pin.
This publication describes the annular flanges as xe2x80x9cflange-like thin-walled dividing wallsxe2x80x9d and is silent as to the function thereof, but a portion of the metal pin between the annular flanges is shown as being used to receive the free end of the magnetic recording tape that is turned and secured in position by the C-clip.
In any event, the single-reel recording tape cartridge in general makes use of a leader piece to ensure a sure withdrawal of the length of magnetic recording tape out of the cartridge housing in cooperation with the catch member. In order for the leader piece to be assuredly drawn of the cartridge housing by the action of the catch member, the leader piece must be retained in the retracted position without being axially displaced and, also, without being tilted when the magnetic recording tape is not in use. In addition, the leader piece held at the retracted position should not displace from the retracted position in any way whatsoever even when external impacts or shocks are applied thereto as a result of, for example, the tape cartridge having been inadvertently dropped onto a floor.
Considering the severe requirement that the leader piece must be retained precisely in proper posture when the tape cartridge is not in use, connection of the tape free end with the metal pin by means of the C-clip creates a high possibility that the tape free end may be connected with the metal pin with its longitudinal axis departing from an orthogonal relation with the metal pin. An additional problem is found in that since the engagement bosses formed integrally with opposite ends of the metal pin are received within generally U-shaped bearing recesses defined in top and bottom panels of the cartridge, one or both of the torsional springs may be dislocated in the event of an inadvertent dropping of the tape cartridge onto, for example, the floor. Once this occurs, the metal pin is, of course, dislodged from the retracted position.
In an attempt to alleviate the problems and inconveniences discussed above, the inventors of the present invention have found that they can be successfully alleviated if the leader member is so structured and configured as to represent a generally U-shaped configuration including a pair of hooking arms and a leader pin having opposite ends connected respectively with the hooking arms. A series of experiments conducted by the inventors have shown that the U-shaped leader member is effective to withstand an external impact or shock and will not therefore be skewed or deformed even when the external impact of shock acts thereon.
More specifically, in order to accomplish the foregoing objective, the present invention provides a single-reel tape cartridge cooperable with an operatively compatible tape drive including a tape catch member, which tape cartridge includes a cartridge housing having a tape window defined therein; a single reel rotatably accommodated within the cartridge housing and having a roll of a length of magnetic recording tape coaxially mounted thereon; a length of leader tape having first and second ends, the first end of the leader tape being connected with a free end of the magnetic recording tape; and a leader member connected with the second end of the leader tape and positioned adjacent the tape window for engagement with the tape catch member when the length of magnetic tape is to be drawn out of the cartridge housing and into the tape drive. The leader member includes a metallic leader pin extending in a direction orthogonal to a lengthwise direction of the magnetic tape and first and second hooking arms and having opposite ends thereof insert-molded into the first and second hooking arms to thereby connect the leader pin with the first and second hooking arms so as to represent a generally U-shaped configuration.
Each of the opposite ends of the leader pin may be formed with a respective anchor which, when insert-molded into the corresponding hooking arm, prevents a rotation of the leader pin relative to such corresponding hooking arm and also separation of such corresponding hooking arm from the leader pin. Preferably, the leader pin has a round sectional shape and each of the opposite ends of the leader pin is flattened to define the anchor of a shape flaring outwardly from the leader pin.
According to the present invention, connection of the leader pin with the hooking arms by the use of an insert-molding technique is particularly advantageous in that not only can the leader pin be accurately positioned relative to the hooking arms at right angles thereto, but also the spacing and parallelism between the hooking arms can be secured with high precision. By way of example, as compared with the leader member wherein after the hooking arms have been molded, the leader pin is connected with the hooking arms with its opposite ends press-fitted into the respective hooking arms, connection of the leader pin with the hooking arms by the use of the insert-molding technique is effective to eliminate variation in final shape of the resultant leader member. Moreover, since the leader pin and the hooking arms can be integrated together during a molding process used to form the hooking arms, no extra process to connect the leader pin with the hooking arms is required, making it possible to provide the leader member at a reduced manufacturing cost.
As compared with the case in which the leader member is constituted solely by a leader pin, the leader member of the U-shaped configuration is so difficult to tilt that the leader pin can be correctly positioned and, consequently, the leader member of the U-shaped configuration can easily be held in a correct posture within the cartridge housing. Accordingly, a tape drawing operation performed by the catch member on the part of the tape drive can be repeatedly performed substantially in a trouble-free manner for a prolonged period of time.
Particularly where the leader pin has an anchor formed on each of the opposite ends thereof, a rotation of the leader pin relative to the hooking arms and, also, a separation of one or both of the hooking arms from the leader pin can be effectively avoided and, accordingly, the leader member can have a robust structure.
In one preferred embodiment of the present invention, each of the first and second hooking arms may have an entry guide face defined therein so as to face in a direction away from the magnetic tape and also has a hooking groove defined in a free end portion of the respective hooking arm so as to extend in a direction generally lengthwise of the corresponding hooking arm while opening laterally towards the leader pin by way of the entry guide face and also towards the other hooking arm.
In another preferred embodiment of the present invention, a releasable lock mechanism may be employed in the single-reel tape cartridge for holding the leader member firmly in a retracted position inside the cartridge housing when the tape cartridge is not in use. In this case, the releasable lock mechanism may include a pair of first lock members and a second lock member cooperable with each other to lock the leader member at the retracted position at which the leader member is housed within the cartridge housing and positioned adjacent the tape window, and a spring element for urging the second lock member towards a locking position. The first lock members may be formed in top and bottom panels of the cartridge housing adjacent the tape window for receiving the leader member at the retracted position in a predetermined posture whereas the second lock member may be positioned in a predetermined posture whereas the second lock member may be positioned within the cartridge housing adjacent the tape window and comprises an elongated lock body reciprocatingly displaceably supported by the cartridge housing for movement between locking and release positions. A biasing spring may be housed within the cartridge housing for urging the elongated lock body towards the locking position so that the second lock member can cooperate with the first lock members to lock the leader member at the retracted position.
Also, according to the present invention, the leader tape is connected with the leader pin in any of methods in a manner effective to avoid a departure of the leader tape from the orthogonal relationship with the leader pin and also to distribute a pulling force, acting on the leader tape, towards one or both of opposite side edges of the leader tape. For this purpose, the leader pin preferably has at least one radial step formed therein for avoiding a displacement of the leader tape relative to the leader pin in a direction axially thereof so that the second end of the magnetic tape can be looped around the leader pin with at least one of opposite side edges of the leader tape held in abutment with the radial step to thereby position the leader tape with respect to the direction axially of the leader pin.
Alternatively, the leader pin may have a large or reduced diameter portion defined at a location axially intermediate of a length of the leader pin. In this case, the second end of the leader tape has to have a cutout defined therein so as to extend inwardly thereof in order to leave two tape end segments that are looped around end portions of the leader pin on respective sides of the intermediate portion thereof with one of opposite side edges of each of the tape end segments held in abutment with the adjacent radial step.
In any event, the radial step preferably has a size equal to or greater than half the thickness of the leader tape. Also, the leader tape is preferably made of a hard tape having some elasticity in order to avoid a possible deformation of one or both of the opposite side edges of the leader tape to thereby avoid a possible displacement in position of the leader tape in a direction axially of the leader pin.